River Management Practices Research Articles

Experimental Study of Bedform Development Characteristics and Their Effects on Sediment Transport

Bedforms are complex and varied features on riverbeds created by the interaction between flow and sediment particles. Bedform evolution is crucial for understanding sediment transport, bed resistance, and the ecological environment of rivers. In this study, a series of movable-bed dune experiments were conducted utilizing advanced 3D topographic laser scanning technology to precisely measure the 2D and 3D dune bedforms under various conditions. This enabled the detailed analysis of the bedform parameters, including the dune length and height, the crest height, and the trough depth. Furthermore, this study examined the relationship between bed resistance and dune morphology and investigated how the intensity of bedload transport affects bed resistance. The findings indicate that bedload mass transport on the riverbed significantly contributes to increased bed resistance. Given the limitations of the traditional bedload transport rate formulas for dune bedforms, this research introduces a new formula derived from the experimental data. The accuracy of this formula was confirmed using the nonlinear least squares method. Our study enhances the accuracy of sediment transport predictions and provides scientific support for river management and engineering practices.

A Framework for Characterizing Spatio-Temporal Variation of Turbidity and Drivers in the Navigable and Turbid River: A Case Study of Xitiaoxi River

Turbidity, as a key indicator of water quality linked to underwater light attenuation, is crucial for evaluating water quality. Control in high-turbidity water environments plays a critical role in navigable rivers. For this purpose, our study proposed a framework for analyzing the spatio-temporal variation of turbidity and its driving factors in a navigable and turbid river using in situ measurement data, satellite data, socioeconomic data, a power index function model, and correlation analysis. The results show that the proposed model is feasible for quantitative turbidity monitoring of the Xitiaoxi River. Its upstream turbidity is lower than downstream, with seasonal averages for spring, summer, autumn, and winter of 93.9, 111.3, 113.5, and 120.9 NTU, respectively. Furthermore, the turbidity in the middle and lower reaches of the Xitiaoxi River continuously increased before 2005 and began to decline after 2005 due to the policy of mining moratorium. This trend is especially noticeable at monitoring points along the main stream of the Xitiaoxi River, such as downstream of the Xitiaoxi River (S1), Gangkou station (S2), middle reaches of the Xitiaoxi River (S4), Hengtangcun station (S6), upper stream of the Xitiaoxi River (S7), and Huxi River (S8). Mining and shipping have significantly contributed to the turbidity of the target river. This framework offers a practical approach for assessing the environmental impacts of both natural and anthropogenic factors, thereby providing valuable insights for river management practices.

Meander geometry characteristics as a response to hydraulic and lithologic control in the active floodplains of Lower Nagar basin

ABSTRACT The present work aims to evaluate the controlling factor of meander geometry in the alluvial rivers. The assimilation of lithologic and hydraulic analysis of the meandering channels puts new insight to the understanding of the meander geometry. The study compares two highly contrasting meandering rivers of Nagar and Kulik in the Lower Nagar Basin, India. To assess the connection between the meandering nature with the hydraulic and lithologic factors, extensive field survey was made during the bank-full monsoon period. The principal component analysis between the hydraulic variables and meandering components suggests that the hydraulic factors of Nagar more effectively control the bend structure of the river, whereas the lithology of the Kulik river controls the meandering planforms. The meander patterns have shown significant transition flowing over different lithologies of grainsize combinations. The statistical prediction based on the hydraulic functions was used to predict the future possible changes in meandering planform. Moreover, the implication of the result was validated with the past century changes and thus can be suitable for the river management practices. In general, the meandering dimensions (in terms of λ, Am and Rc) are found to be maximized when finer materials are prevalent and vice-versa.

Drought impacts on river water temperature: A process‐based understanding from temperate climates

AbstractHigh river water temperature (Tw) extremes have been widely reported during drought conditions as extreme low‐flows often coincide with high atmospheric energy inputs. This has significant implications for freshwater ecosystem health and sustainable river management practices globally. However, the extent to which different meteorological and hydrological processes interact during droughts to govern Tw dynamics, and how this varies between environmental contexts, remains poorly understood. Here, we review the mechanisms controlling Tw dynamics during droughts across temperate, maritime environments, using the United Kingdom as a detailed case study. We evidence that Tw spikes have widely occurred during extreme low‐flow events observed within droughts, but such trends have been inconsistent due to varying hydroclimatic conditions and river basin controls. To better understand this, we re‐conceptualize the mechanisms governing drought‐induced Tw dynamics operating across three ‘process sets’: (i) ‘energy flux dynamics’ as non‐advective controls on Tw; (ii) the role of ‘reach‐scale habitat conditions’ in mediating non‐advective controls on Tw, including hydraulic properties (e.g., residence time) and physical conditions (e.g., riparian vegetation coverages, wetted perimeters); (iii) ‘water source contributions’ (surface water and groundwater) as advective heat and water flow controls. We review natural and anthropogenic influences affecting Tw controls within each process set and discuss how such mechanisms are likely to change under drought conditions. More systematic research (spanning various river environments and drought severities) is required to test such concepts, with existing scientific knowledge on drought‐induced Tw dynamics being largely gleaned from studies examining non‐extreme low‐flow conditions or with broader focuses (e.g., annual thermal dynamics). We conclude by highlighting critical future research questions that need to be answered to better model Tw dynamics during future droughts and for unmonitored sites. Such scientific advances would more effectively inform how high Tw extremes could be better managed through evidence‐based mitigation and adaptation strategies.

Evaluating the physical habitat of riffle‐pool design in support of river habitat protection and rehabilitation

AbstractRiffle‐pool constructions are common practice in river management and fish conservation, but insufficient science exists to guide objective design of riffle‐pool. Understanding the spatial design of a riffle‐pool in river systems has significant value because it can provide important information to ameliorate aquatic species decline. In this study, six types of riffle‐pool structures were designed to assess hydrodynamic and riverbed morphology effects on stream habitat status. A two‐dimensional ecohydraulic model was used to assess the roles of different riffle‐pool designs in river habitat conditions. The natural flow condition and three types of flood flow conditions were applied to the six types of riffle‐pool structures to evaluate the habitat quality and the sustainability of the riffle‐pool design in mountain rivers. The long‐term impacts of the hydrodynamic and hydromorphology conditions on river physical habitat status were also analysed. The results indicate substantial differences in habitat quality among six riffle‐pool structures. It was found that narrow riffle‐pool construction yielded the best performance for the fish habitat, which had the best habitat quality among six riffle‐pool designs with the smallest pool area. In the same riffle‐pool structure, the habitat suitability in the riffle‐pool sequence will primarily increase more rapidly and then decrease gradually along with the discharge increase. Under the flood discharge scenarios, low flood discharge could improve riffle‐pool habitat quality, while high flood discharge could fragment the riffle‐pool habitat quality further. The long‐term hydrodynamic conditions have the same effects on all six cases. Overall, low discharge and smaller pool design would be beneficial to the river system, which could help maintain habitat diversity of mountain rivers. This analysis could provide valuable information for river management and decision‐making, which could assist in designing better mountain river habitats to promote conservation and rehabilitation of endangered biota.

Mode decomposition based large margin distribution machines for sediment load prediction

Precise suspended sediment load (SSL) prediction is essential for irrigation, hydropower and river management practices. But due to some external factors such as high altitude, heavy monsoon and tropical climate conditions, the data we collect may contain noisy samples. Hence, it becomes a challenging task to accurately predict the SSL in rivers. Therefore, to diminish the influence of noise, the empirical mode decomposition (EMD) -based techniques can be adopted. Moreover, the large margin distribution machine-based regression (LDMR) can deal efficiently with noisy datasets as it simultaneously minimizes the insensitive loss as well as quadratic loss. The significance of this work lies in its contribution to improving the accuracy of suspended sediment load (SSL) prediction in rivers, which has practical implications for various applications such as irrigation, hydropower, and river management. We recognize the challenges posed by external factors, which introduce noise into the collected data, making accurate prediction of SSL difficult. Overall, the significance of this work lies in its novel integration of EMD-based techniques and LDMR-based models, which address the challenges posed by noisy and non-stationary sediment load data. The findings contribute to the field of SSL prediction, offering practical solutions for managing and utilizing river resources more effectively in various domains. The main advantage of the least squares LDMR (LS-LDMR) approach is that it solves a system of linear equations rather than solving a large QPPs unlike SVR, TSVR, LDMR, which makes it computationally efficient. It is well known that the sediment load data is complex and non-stationary in nature. Therefore, for daily SSL prediction, the LDMR and least squares LDMR (LSLDMR) models are embedded with two different decomposition techniques, EMD and ensemble EMD (EEMD), to handle the nonlinear and non-stationary characteristics of sediment load data on the forecasted outputs and to increase prediction ability. The results of the proposed EMD-LDMR, EEMD-LDMR, EMD-LSLDMR and EEMD-LSLDMR are compared with the conventional support vector regression (SVR), twin SVR (TSVR), LDMR and LSLDMR. The performance of the evaluated using the best-fit model using the mean absolute error (MAE), root mean square error (RMSE), symmetric mean absolute percentage error (SMAPE), Willmott’s index (WI), correlation coefficient (CC) and R2. Better or comparable results specify the efficiency of the suggested models. For graphical visualization, scatterplots, prediction error plots and violin plots are shown. Numerical results show that these hybrid models show excellent prediction performance. The overall analysis of the results suggests using EEMD-LSLDMR for SSL estimation.

Trends in post‐1950 riparian vegetation recovery in coastal catchments of NSW Australia: Implications for remote sensing analysis, forecasting and river management

AbstractExtensive riparian vegetation clearance occurred in many rivers of southeastern Australia throughout the 19th and 20th century, post colonisation. With improvements in river management practices, coincident with a period of minimal flooding, vegetation recovery of riparian corridors has been occurring since the 1980s in all coastal catchments of New South Wales (NSW). However, the catchment‐by‐catchment spatial pattern and temporal trends, trajectories and rates of vegetative recovery remain unknown. We reconstruct a 70‐year time series of change in riparian vegetation coverage for all rivers in coastal catchments of NSW, utilising historical aerial imagery, Landsat and Sentinel data and a manual digitisation and machine learning method. We quantify and statistically analyse decadal trends in woody and non‐woody vegetation coverage along 19 485 km of stream length in 20 catchments. Across the region, there has been, on average, a 40% increase in vegetation coverage along riparian corridors since the 1950s, with some catchments increasing towards a current day coverage of between 60% and 80%. However, the trends vary by subregion and by catchment. An early logarithmic increase occurred up to 2004 on the North coast, and a recent and accelerated exponential increase since 1995 has occurred on the South coast. After a steep initial increase, riparian corridor vegetation coverage has fluctuated on the Central coast since about 1995. We used these linear, exponential and logarithmic regressions to undertake preliminary forecasts of possible future timeframes of riparian vegetation change, based on several climate, management and natural disaster disturbance scenarios. If the current trend continues, riparian vegetation coverage can reach 70% across the region by 2055. However, if management practices change or catastrophic disturbance events such as fire and flood occur, increases in riparian vegetation coverage could be set back by up to 30 to 40 years.

Active distributed temperature sensing to assess surface water–groundwater interaction and river loss in braided river systems

Braided river systems are continuously changing environments, comprising heterogeneous gravel-forming meandering channels and bars, and dynamic surface water–groundwater (SW–GW) interactions. In alluvial aquifers associated with braided rivers, river leakage is volumetrically the most important source of groundwater recharge, yet neither the leakage process or recharge rates are well understood. Insights into how braided river systems recharge underlying braidplain aquifers during different hydrological conditions, and how this can be measured, is of critical concern for river management practices. Innovative field techniques using heat as a tracer can be applied to spatially map and quantify the temporal changes of SW–GW interaction and the processes and mechanisms of groundwater recharge for different flow regimes. Horizontal directional drilling was used to construct two 100 m long drillholes at a depth of ∼ 5 m beneath and perpendicular to the river channel at a field site on the Waikirikiri Selwyn River, South Island, New Zealand. The two drillholes were completed with a hybrid fibre optic cable, containing four multi-mode fibres and 2x18AWG copper conductors. A Silixa XT-DTS™ distributed temperature sensor unit combined with a Silixa Heat Pulse System, was used to collect active distributed temperature sensing (A-DTS) measurements along both cables. Results from two A-DTS surveys showed distinct temperature changes across the active river channel indicating spatial variability in river loss and preferential groundwater recharge pathways to the shallow braidplain aquifer. The average groundwater velocity was 14 m d−1. The average calculated river loss at the survey sites was 21 m3 d−1 m−1 compared to 25 – 26 m3 d−1 m−1 that was measured using differential flow gauging conducted during the same time period. The horizontal installation of the fibre optic cable and the A-DTS method provided valuable insights into SW–GW exchange between the Waikirikiri Selwyn River and shallow braidplain aquifer and how the river leakage rates varied spatially across the river channel.

Spatio-temporal differences dominate suspended sediment dynamics in medium-sized catchments in central Germany

Suspended sediment transport, dominating material export from lowland river systems, is highly variable in space and time. Since suspended sediment transport can have adverse effects on human infrastructure, targeted management is imperative. To achieve this, a thorough understanding of suspended sediment dynamics is needed, but requires long-term monitoring data. Despite studies investigating suspended sediment dynamics on decadal time scales, an assessment of the spatio-temporal variability across adjacent river catchments is still lacking.To fill this gap, we analyse suspended sediment transport at twelve stations along German upland rivers, monitored on a daily basis for 28 to 54 years. All monitoring stations belong to the Rhine (Lahn, Lippe, Main, and Neckar) and Weser river systems (Fulda, Leine, Werra, and Weser) and have contributing areas between 2500 and 22,000 km2. Although located in comparable topo-climatic settings, average sediment yield for the monitoring period varied more than fourfold. Covering the range of 5.9 to 28.7 t km−2 yr−1, we found the highest and lowest suspended sediment yields for the Neckar and Lippe catchments, respectively. Using two different streamflow separation approaches, we estimated the contribution of stormflow discharge to total sediment transport to fall between 73 and 85 % in the Neckar and Lahn rivers while remaining ~15 % lower for the remaining catchments. Investigating the relevance of extreme events, we found the share of total suspended sediment load transported during the ten largest events to vary between ~28 % for the Neckar and ~8 % for the Lippe and Werra catchments. These events were predominantly characterized by clockwise hysteresis loops that hint to in-channel reworking as a significant material source, with the exception of the Neckar stations where anti-clockwise hysteresis patterns prevailed. Here, the hysteresis analysis indicates sediment delivery from more distant sources in the headwater regions, likely related to elevated rainfall intensities and the susceptibility of the escarpment of the Swabian Alb towards landsliding. We conclude that the combined effect of varying rainfall amounts and intensities, the fraction of steeper slopes as well as lithological differences explain the across-catchment variability on multiple time scales that is further modulated by river management practices.

Developing an empirical model for climate change adaptation in river management planning using DPSIR framework at Nabaganga river of Narail district, Bangladesh

This study investigated the integration of ecosystem services and climate change adaption in river management planning in Bangladesh. The research was carried out in the selected villages with high vulnerability to climate change, namely Lohagara, Kalachandpur of Lohagara upazilla, Gazirhat of Kalia Upazila, and Narail. The survey was conducted by collecting data from both primary and secondary sources. For collecting primary data, different methods had been adopted including informal interviews, a semi-structured questionnaire survey and Focus Group Discussion (FGD). The present study modified the DPSIR framework to add connection that allows for the integration of ecosystem services and climate change responses in a future management plan. In this study, temperature and precipitation, changes in water level of the river from 1982 to 2020, rainfall pattern from 1984-2021 and yearly salinity level series of the river from 2014-2021 were analyzed for assessing the climate change impact on the river ecosystem. The changes in fish species diversity were also interpreted in this study and observed that 41 species were available in 2014 but now it has been reduced to 37 species. Some salinity tolerant species were found to be available recently due to salinity intrusion. In this study, the present river management practice was compared with community perception by SOWL analysis. The empirical model applied in this study is intended to support adaptation planning and monitoring and can not only be used in Nabaganga River but also in other vulnerable riverine ecosystems to climate change in Bangladesh.

Identifying corridors of river recovery in coastal NSW Australia, for use in river management decision support and prioritisation systems.

By connecting corridors of river recovery, resilience can be built into river systems to mitigate against future floods and droughts driven by anthropogenic disturbance or climate extremes. However, identifying where these corridors can be built is still lacking in river management practice. The Open Access NSW River Styles database contains comprehensive information on geomorphic river condition and recovery potential. The database can be used to systematically analyse where corridors of river recovery could be created via conservation or rehabilitation. Analysis was undertaken in ArcGIS using the recovery potential layer along 84,342 km of freshwater stream length, across 20 catchments of coastal NSW. We identified 4,905 km of reach connections, defined as an upstream to downstream section of river that is connected end-to-end, and 17,429 km of loci connections defined as more isolated sections of river from which recovery can be seeded and extended into adjacent reaches. There was significant spatial variability in the types and lengths of connections made across the catchments. Some catchments have significant potential to build corridors of recovery along large sections of river, whereas other catchments are more fragmented. These results provide practitioners with a user-friendly distillation of where river conservation and rehabilitation activities could be focussed when working with river recovery in practice. Combined with local on-ground knowledge, this information forms an important input to evidence-based prioritisation and decision making in river management.

A new index of a water temperature equivalent for summer respiration conditions of benthic invertebrates in rivers as a bio-indicator of global climate change

Detailed information on species temperature preferences are needed to measure the effects of global warming on species and communities in European rivers. However, information currently available in the literature on taxon-specific temperature preferences or temperature tolerances is very heterogeneous and therefore not well suited for forecasting purposes. To close this gap, we derived so-called 'central temperature tendencies' (CTTt values) for benthic invertebrate species. For this end, 547 species and temperature data from regional monitoring programmes in Germany collected at 4249 sites were analysed. Due to the vulnerability of species to high temperatures, CTTt values were calculated for mean summer temperatures, following a robust approach of calculating a weighted average based on temperature classes. Derived CTTt values correspond well to species temperature preferences as reported in literature as long as the latter were homogeneous in terms of how they were derived and which temperature reference was at focus. Based on taxon-specific CTTt values, a community value, CTTCom, was calculated for each benthic invertebrate sample. CTTCom values were validated by correlation with mean summer water temperatures. As the slope a of the linear regression model between CTTCom values and measured summer temperatures was comparatively low (a = 0.49), a correction function was derived in order to optimise the relation between both. This was crucial, because it is assumed that although CTTt was derived solely from taxa abundances within summer temperature classes, CTTCom not only reflects the effect of (summer) water temperature itself, but also corresponds to a temperature equivalent value, which describes the overall quality of all respiration-relevant aquatic summer habitat conditions that determine the metabolism of respective benthic invertebrates. By comparing this equivalent value with water temperatures measured in the year previous of sampling, statements can be made about the influence of flow conditions and other factors determining oxygen availability.Thus, CTTCom reflects the mean aerobic scope of the overall benthic invertebrate fauna: the better the respiration conditions for rheophilic species with high oxygen demand, the larger the aerobic scope and the lower CTTCom.The approach taken in our study is promising and provides a tool to track and even project past, present, and future impacts of global warming on benthic invertebrates in rivers based on measured values of respiratory relevant environmental variables. We encourage all stakeholders in the field of freshwater ecology to test this tool, which is already in use in river management practice in Germany and is known under the long or short terms KLIWA-IndexMZB or KIMZB.

Prediction of floodwater impacts on vehicle blockages at bridges using artificial neural network

During extreme flood events, various debris like floating vehicles can block the bridges in urban rivers and floodplains. Blockage of vehicles can influence the floodwater hydrodynamics and potentially on the flood risk implications. Such obstructions often raise upstream water levels with back water effects, causing more water to be redirected into nearby metropolitan areas. This study attempts at evaluating artificial neural network (ANN) model in predicting the variations in floodwater depths and velocities along the channel centreline based on the changes in flowrate and distances from the inlet. The floodwater depth and velocity variations were obtained for three different types of bridges at specified sites along the channel centreline with three incoming discharges. A multilayer feedforward neural network (FFNN) model was used to investigate the effects of discharge (Q) and distance, on depth variation rate (D) or velocity (V). Additionally, a comparison study was done between 2 input 1 output and 2 input 2 output i.e. single output (depth variation rate (D) or velocity (V) versus multi-output depth variation rate (D) and velocity (V) for all the three models of bridges that are blocked by vehicles. The study has applied 12 training algorithms (TA) in the ANN modelling to optimize the TA that is most suitable for the dataset of three different bridges. The optimization is based on the performance criterion namely regression (R), mean squared error (MSE), mean absolute error (MAE), mean absolute percentage (MAPE), accuracy and coefficient of determinant (R2). Bayesian regularization backpropagation (BR) training algorithm gives a highest accuracy when compared in all three bridges. The scenario 2 input 2 output gave greatest accuracy results compared to 2 input 1 output. The findings showed a reliable estimation of significant impacts on the flow propagations and the hydrodynamic processes along rivers and floodplains. This study can help the decision makers in effective river and floodplain management practices.

From meta-system theory to the sustainable management of rivers in the Anthropocene.

Regional‐scale ecological processes, such as the spatial flows of material, energy, and organisms, are fundamental for maintaining biodiversity and ecosystem functioning in river networks. Yet these processes remain largely overlooked in most river management practices and underlying policies. Here, we propose adoption of a meta‐system approach, where regional processes acting at different levels of ecological organization – populations, communities, and ecosystems – are integrated into conventional river conservation, restoration, and biomonitoring. We also describe a series of measurements and indicators that could be assimilated into the implementation of relevant biodiversity and environmental policies. Finally, we highlight the need for alternative management strategies that can guide practitioners toward applying recent advances in ecology to preserve and restore river ecosystems and the ecosystem services they provide, in the context of increasing alteration of river network connectivity worldwide.

Automated analysis of lateral river connectivity and fish stranding risks. Part 2: Juvenile Chinook salmon stranding at a river rehabilitation site

AbstractThe dynamics of fish stranding have not been academically investigated within the context of physical adjustments to rivers for habitat enhancement purposes. River projects may aim to help fish populations but instead may function as attractive nuisances reducing populations because of unaccounted‐for stranding risk. This study applies a novel algorithm to predict spatially explicit, meter‐resolution fish stranding risk at a river rehabilitation site in California to address three scientific questions. Postproject disconnected wetted area predictions were validated against water surface elevation measurements and time lapse photography of flow reductions and stranding events. A comparison of preproject, final design, and postproject topographies revealed that the occurrence and severity of stranding events is highly sensitive to side‐channel topographic structure and postproject morphodynamic change. Even with moderate flows, side‐channel exits tend to close off by bars built across them via bedload transport. Implications for river management practices and river rehabilitation project design are discussed.

Aquatic habitat changes within the channelized and impounded Arkansas River, Arkansas, USA

AbstractRiver‐wide changes in morphologic character following channelization and impoundment alter the occurrence and distribution of surface water and available habitats for aquatic organisms. Quantifying patterns of creation, redistribution or disappearance of habitats at river‐wide and decadal spatiotemporal scales can promote understanding regarding trajectories of different habitat types following alteration and prospects of direct habitat enhancement projects within altered alluvial rivers. Newly available remote‐sensing tools and databases may improve detection of river‐wide changes in habitat through time. We used a combination of remote‐sensing data and generalized linear models to assess changes in surface water coverage from 1984 to 2015 among aquatic habitats of 496 km of the Arkansas River within Arkansas, USA. Changes through time in surface area of permanent and episodically inundated areas — and thus the availability of aquatic habitat — were variable along the river. Overall, the river lost a total 2.1% of permanent and 12.1% of episodic water surface area. The general trend of loss of off‐main‐channel habitat and increased coverage of permanent water along main‐channel habitats may indicate a long‐term transition (i.e. ramp‐type disturbance) within areas of the Arkansas River where backwaters are transitioning to terrestrial environments, and habitat heterogeneity in the main channel is decreasing. As such, a decadal‐scale change of channel form and backwater habitats may be the dominant pattern with limited regeneration of diverse habitat types. Understanding changes to permanent and episodic water availability may aid predictions regarding ecological effects of channelization and impoundments, including both increases and decreases in riverine productivity, biotic diversity and population abundances through space and time. Water resource managers and biologists can use information regarding river‐wide changes in habitat availability obtained through remote sensing data to direct river management practices, including dredging and side‐channel construction, and to assess ecological responses to such changes.

When experts feel threatened: Strategies of depoliticisation in participatory river restoration projects

This paper explores how experts involved in river management projects in Switzerland consider public participation. It reflects on the consequences that these considerations have on the potential for participation to become a political space. Public participation has become a standard practice in river management at the European level since the 1990s. In Switzerland, the federal government incentivises public participation in river‐work projects through guidelines and additional subsidies for projects planned in a participatory way, with the goal of avoiding costly conflicts. Based on an analysis of expert discourses, we examine how experts activate three different arguments to depoliticise participation: that participation should be implemented to ensure acceptance of the project; that the exclusion of some actors is justified based on assumptions about the type of knowledge required for participation; and that disagreement should not be expressed within participatory processes but through representative politics. We conclude that the consistent motivation of experts to depoliticise also indicates a potential for participation to become political, which is worth exploring with new perspectives for engaging the public.

Local environmental, geo-climatic and spatial factors interact to drive community distributions and diversity patterns of stream benthic algae, macroinvertebrates and fishes in a large basin, Northeast China

Understanding processes and mechanisms driving patterns of species distribution and diversity is a vital theme in community ecology and conservation biology. There has been a continuous increase in studies focusing on diversity patterns in freshwater ecosystems during the last few decades. However, comparative studies of species distributions, diversity patterns and underlying processes across trophic levels remain limited. The unique characteristics of the study area (i.e. Hun-Tai River in Northeast China) generates a wide range of environmental conditions to advance our understanding of what drives community assembly and diversity pattern of three stream organism groups. We applied variance partitioning (VPA) to correlate community compositions with environmental and spatial factors to infer stochastic and deterministic assembly processes, respectively. Linear regression (LR) models were used to identify the main drivers of species richness and local contributions to beta diversity (LCBD) as a function of different factors, including local environmental (e.g., in situ parameters, hydrology, nutrients), geo-climatic variables (e.g., land use, topography, climate) and spatial factors. Results indicated that species compositions of stream biota showed significant correlations with local environmental, geo-climatic and spatial factors. VPA demonstrated that both paradigms (i.e. deterministic and stochastic processes) interact to influence the biota distributions with stochastic process contributing more than deterministic process. In addition, the strongest stochastic process was found in fishes (10%), followed by benthic algae and macroinvertebrates with the same effects (8%). Notably, geo-climatic factors explained a substantial fraction of species composition, richness and beta diversity, although their effects were partially manifested via local and spatial variables. We demonstrate the relative importance of both stochastic and deterministic processes in shaping community composition and biodiversity of three stream organism groups in a large basin. This emphasizes the need to move beyond observed patterns and consider metacommunity theory into river management and conservation practices.

Pollution impacts on the aquatic ecosystems of the Kruger National Park, South Africa

The Kruger National Park (KNP) is a savanna ecosystem situated in the middle reaches of five large, dynamic and biologically diverse transboundary river systems. The KNP has been at the forefront of applied river ecosystems research for over 30 years. Meanwhile each of its rivers has a unique set of challenges from both a river flow and water quality management perspective. These have often arisen from anthropogenic changes in the catchments of the park. The resultant challenges give rise to an array of effects that bear upon the parks’ ability to maintain the viability of aquatic ecosystems in a large and bio-diverse landscape. This paper sets the scene through a synopsis of the investments made by the KNP to improve river management practices and the present status-quo of these aquatic systems. Moreover, it details through particular case studies where emergent impacts of diffuse pollution sources have affected the aquatic biotic processes within the park and downstream. Issues are framed within a conservation management context with respect to broad ecosystem health and species of conservation concern. Comparisons are also made to other aquatic ecosystems within the KNP where the impacts of diffuse pollution effects are as yet unapparent.

LEARNING, DOING AND PROFESSIONAL DEVELOPMENT – THE RIVER STYLES FRAMEWORK AS A TOOL TO SUPPORT THE DEVELOPMENT OF COHERENT AND STRATEGIC APPROACHES FOR LAND AND WATER MANAGEMENT IN BRAZIL

Ongoing development, training and adaptive learning are fundamental to professional practice in river science and management. River Styles Framework provides a coherent, carefully structured (scaffolded) approach that synthesises geomorphic understandings of rivers as a baseline to support river management applications. As the approach is generic, principles and procedures can applied in any setting. The Framework and its applications build on fundamental research into river forms and processes. Importantly, the Framework was developed in collaboration with river management agencies in New South Wales, Australia and has been used in collaboration with practitioners elsewhere in the world. This paper documents the process used to teach the five-day River Styles professional short course in Brazil, September 2017. We report upon some pedagogical foundations of the Framework to explain the approach to teaching. We present an overview of the types of exercises taught in Brazil, showing how local fieldwork and case studies support the uptake of this geomorphic information to inform river management. We emphasise the importance of careful planning in delivering a coherent product that integrates remotely-sensed work, field interpretation skills and lecture/practical class exercises. These exercises build upon foundation research in fluvial geomorphology in the Macaé Catchment in Rio de Janeiro State.